Technical Pitfalls of Insulin Pump Clock
Oct 17, 2012, 05:00 AM
Special guest blog from Saleh Aldasouqi, MD, FACE, ECNU, Associate Professor of Medicine, Michigan State University College of Human Medicine, East Lansing, and Director of Sparrow Diabetes Center, Lansing, Michigan
My team at Michigan State University and Sparrow Diabetes Center presented a poster at the 2012 AADE Annual Meeting that received considerable attention. A pump manufacturer recently circulated a warning to users regarding a “glitch” in its software that didn’t recognize the 2012 leap day (February 29th). This could cause a basal insulin delivery or a recommended bolus amount that is incorrect for the actual time of day and could result in unexpected high or low blood sugars.
We recently encountered a similar issue related to a pump’s clock set up. An 18-year old international college student with type 1 diabetes had been using an insulin pump, which she started in her native country (where no seasonal daylight savings time changes occur). When we saw her in clinic this summer, her pump’s clock was one hour late because she didn’t realize the need to manually change the clock in the spring. Fortunately, no significant harm resulted from the incorrect setting, given the trivial time difference. However, while the daylight savings time change may not cause serious harm with just one hour difference, we do foresee a more serious problem with regards to 12-hour (AM, PM) versus 24-hour formatting. For example, if the pump’s clock is not set up correctly (e.g., PM instead of AM), this may result in incorrect insulin delivery; the patient may then receive the PM basal rate (usually higher) at midnight, potentially causing nocturnal hypoglycemia. Therefore, in order to avoid this human error, it is safer to use the 24-hour format.
It’s important that patients set up their pumps’ time and date correctly at all times. But insulin pump manufacturers can also help prevent such technical pitfalls. They constantly educate patients about all safety issues related to insulin pumps, including time and date set up, which is helpful. However, relevant technical improvements are desirable, such as equipping insulin pumps with built-in automatic time and date adjustment, or even equipping pumps with GPS connectivity which would guarantee that pumps clocks automatically adjust when patients travel across time zones.
However, until all pumps are equipped with automatic time and date adjustment, I recommend diabetes educators to inform their patients about adjustments for seasonal time and date changes, to pay attention to current date and time settings of their pumps, and to constantly verify that the pump clocks are set up correctly at all times.